What Are Brain and Nervous System Tumors?

There are many types of brain and spinal cord tumors. Together, the brain and spinal cord make up the central nervous system (CNS).

Tumors can be classified into two main types: benign and malignant.

Benign tumors are noncancerous and slow growing. They rarely spread to other parts of the body, but grow locally in the region they originated from. This type of tumor is often treated by surgical resection.

Malignant tumors are cancerous and are more difficult to treat. Malignant tumors grow rapidly, usually invading surrounding brain and nerve tissue.

Malignant tumors of the brain and spinal cord can be further classified as primary or secondary tumors.

Primary brain tumors, also known as primary brain cancer, originate in the brain and rarely spread to other parts of the body. Primary brain tumors are named from the cells in which they originate.

Secondary brain tumors, also known as metastatic brain cancer, originate from cancer cells in another part of the body which have spread to the brain. The most common places for the cancer cells to travel from include the lung, breast, and melanoma, but almost all cancers can spread to the brain.

Risk Factors for Brain and Nervous System Tumors

Some factors that may increase risk for developing a brain tumor are:

Age – Brain tumors can occur at any age, but studies show that they are most common in two age groups: children, 3 to 12 years old and adults, 40 to 70 years old.

Occupation – Studies show that some types of brain tumors are more frequent among workers in certain industries, such as oil refining, rubber manufacturing, and drug manufacturing. Other studies have shown that chemists and embalmers have a higher incidence of brain tumors.

Radiation exposure – Some studies have connected brain tumors and a specific type of radiation, called ionizing radiation, which typically comes from cancer treatment or exposure to nuclear weapons. More common types of radiation (from electronic devices or power lines) have not been linked to tumors.

Scientists do not believe that head injuries cause brain tumors to develop.